From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7F86C83F1A for ; Tue, 22 Jul 2025 05:42:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 818178E0003; Tue, 22 Jul 2025 01:42:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7C8C88E0001; Tue, 22 Jul 2025 01:42:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6B8198E0003; Tue, 22 Jul 2025 01:42:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 5C8B38E0001 for ; Tue, 22 Jul 2025 01:42:43 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 076EC80271 for ; Tue, 22 Jul 2025 05:42:43 +0000 (UTC) X-FDA: 83690806206.06.AF89210 Received: from NAM02-DM3-obe.outbound.protection.outlook.com (mail-dm3nam02on2068.outbound.protection.outlook.com [40.107.95.68]) by imf20.hostedemail.com (Postfix) with ESMTP id 405E91C0007 for ; Tue, 22 Jul 2025 05:42:40 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="oawuO/md"; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf20.hostedemail.com: domain of ymaman@nvidia.com designates 40.107.95.68 as permitted sender) smtp.mailfrom=ymaman@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1753162960; a=rsa-sha256; cv=pass; b=0ORUNzTVc2SYEtDHcl+PQoI1EuwTZeq3HnYO9r8DlYou9M/8gQa4eP+oFnKm4H0OkHxT5X VGDCBggGnSaWlreapaqZrVWv30WQQGfdI/wIK2VFZfTWFwS9X2Gj1qdGmjuBIt5uCvi3q9 kAGsoDRotnjUINyDd9knHou8naDPNnM= ARC-Authentication-Results: i=2; imf20.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="oawuO/md"; dmarc=pass (policy=reject) header.from=nvidia.com; spf=pass (imf20.hostedemail.com: domain of ymaman@nvidia.com designates 40.107.95.68 as permitted sender) smtp.mailfrom=ymaman@nvidia.com; arc=pass ("microsoft.com:s=arcselector10001:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1753162960; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MdZN/D7pasYBLufWKrVTXTveKM/eDH45g9TxEw9CPqQ=; b=b6TBc3tRq8MdCIwCIBu+fJstkk9JFUXhWfJAP+4FASaRQKjHwQuqeoCAynz6HC+owpP1Lt C9HyM4cRIHlcwDa5rSgExIf9I7DL0HEK14F61im6V4o4H1KwxfFvhTDz2Uy+rePTCs7Le+ /D+c1SB/mYM8HUuGwELeTKOMDtsVZl8= ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=n3bTmwE+isBI1MGfYnIgJvo8maWsJRZSIt8AZUNwrGO5cuuC/P1f+v781sYy6vowrWLkuJ/mYGcE1TEiTGhth9nu3zezS+MEERon2AEnfBmOeQHLYANY5WsqcXMumj9wdm209rPGk2wo08q0d3vrmYbHw7uSJbtkEld61wrHViMHZxSha8tNypFK93rD+gCav045+UEPLFGvom6DDuszmpAvXbGC1Fibfbhy/vjvAt0ejWVd35ioOmW1W3//FQN7Svvn4f0i9Rrj1RpeKXFFFvU85YDNZD95gx/H0BinVLy4WMrnuMuMvG05+RwiIcedTWFP2jLzTy/gJj1AcO606A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=MdZN/D7pasYBLufWKrVTXTveKM/eDH45g9TxEw9CPqQ=; b=eLp01jazV1fdduSsHVClUxTfbNhjW9ltNUgHWqG3xEy9uTesRRd6LNU4K/3YIqaksrAdcQ1GOJq02gQDPXUeT0+021NgtboBpFlRb39obTtP5HtKO61uKieouYDbHNMUi75oXdKSxTCYlBQzGRctIN5MAhuTcdbWaUgxYGxZ8CljI2DIqxErreA4VVpzzKK6IqEYsjorjxgMWTgYl/H+IvBhtJNLCl8H2vSLQNnFvQkZ2uE0hIWILi89R/9gVqJkg/aUsaGq2KrAsDktKJU4QOzGPaGg2D2VyfbCXmD0BdVLS9RH3TLoPZnjDqhx3kIody8oQGWxco2DG+txxoiJWg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=MdZN/D7pasYBLufWKrVTXTveKM/eDH45g9TxEw9CPqQ=; b=oawuO/mdNiwRDm5a/WBvI7voBmshh7cFhK4kF89XWpF4YkbkafZcpeurDNKD0Q4KC0Nom5V+8s4PVauCe1x+MkFmMy52cMvGYmB1joiIATQf+EDSphrV1kveeJwB7UWaFDqNSux0m8C0/iVaxSI/WYRGc2xUpfMxUyvyUJw9lElEHfn72c8aOR4TqxNH9dguN1KT8bSKp/A//DqaC560RlCGcj+sGoCokonYcostioOWb1GLgGYKU0TAu+VB3V7VGrx5u4ixdGsCKxuH8OGNqRX0UR8kPFZIRZBAH0WXlDuTKmhC3DbM2lUnV2Hu66xeoi//i+8yU0s4b/w/JVtk6g== Received: from BL1PR12MB5851.namprd12.prod.outlook.com (2603:10b6:208:396::13) by SA3PR12MB9226.namprd12.prod.outlook.com (2603:10b6:806:396::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8922.40; Tue, 22 Jul 2025 05:42:37 +0000 Received: from BL1PR12MB5851.namprd12.prod.outlook.com ([fe80::d4a:9ce3:c92e:e938]) by BL1PR12MB5851.namprd12.prod.outlook.com ([fe80::d4a:9ce3:c92e:e938%4]) with mapi id 15.20.8922.037; Tue, 22 Jul 2025 05:42:37 +0000 Message-ID: <419c7a17-b20f-41b9-88af-f9f83c8611ef@nvidia.com> Date: Tue, 22 Jul 2025 08:42:30 +0300 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 1/5] mm/hmm: HMM API to enable P2P DMA for device private pages To: Christoph Hellwig Cc: =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Andrew Morton , Jason Gunthorpe , Leon Romanovsky , Lyude Paul , Danilo Krummrich , David Airlie , Simona Vetter , Alistair Popple , Ben Skeggs , Michael Guralnik , Or Har-Toov , Daisuke Matsuda , Shay Drory , linux-mm@kvack.org, linux-rdma@vger.kernel.org, dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org, linux-kernel@vger.kernel.org, Gal Shalom References: <20250718115112.3881129-1-ymaman@nvidia.com> <20250718115112.3881129-2-ymaman@nvidia.com> Content-Language: en-US From: Yonatan Maman In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: TL2P290CA0006.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:2::6) To BL1PR12MB5851.namprd12.prod.outlook.com (2603:10b6:208:396::13) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL1PR12MB5851:EE_|SA3PR12MB9226:EE_ X-MS-Office365-Filtering-Correlation-Id: fc4fb341-882a-4a19-dee7-08ddc8e29088 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|7416014|10070799003|1800799024; X-Microsoft-Antispam-Message-Info: =?utf-8?B?a3l3YVpGSXc4L29FeXRkeUFoVnhBYVB3TlhlSWdQSXJvbWgzdjJiZVBtWUsz?= =?utf-8?B?VTd0SEFtUTQzY2dMa2xjN2h6MGZUVEZDaW9oWmlHVmNodHR1enFKcFoxTGFF?= =?utf-8?B?WTVLOGVWdGZNYnhGb2dwMnlBajh6RmVjdE1mTitDcVY2cTFZRjhMOTNnNDBy?= =?utf-8?B?Vmh6WGZqNVgva3h6ZXM2MGpsRFMwZXUrVTg1YTVaYzN5U3hoOWk2L0dZcTN5?= =?utf-8?B?bmdDRExzeTZja082MVdvOFVZV0FCYVJ0YTBWbStENi92K01kQ2NlS0ZlbDBa?= =?utf-8?B?bVgvR0lreTJRU1ZmL001REpOajB3aFRPVGlMTi9RelRQcFFhdHdUNWIxUisw?= =?utf-8?B?MlBucnBMT0M0NXJMczJyNkw2dEYveXdidDZjaHdOY3Q1NGsyOWdSQnRVSmVB?= =?utf-8?B?bXh3VVVyY0krelMxNElrdVBZU2VhTjJ6TmovdW5nYjJFQVE4OUZxeUgrbi9V?= =?utf-8?B?T0lpRTVQOXo0SUJ1c3BRblYwdEE1bnEwQWlydDBjY3AzOUNtUkIxRW95ZHBM?= =?utf-8?B?Y0s4OG50cHhJQmlFNlY3WG5RaFY5dDJGN2FtWHZzRURLS0JIM2lVRXNsa28x?= =?utf-8?B?RUpFeDhnMGFNMkxrNFlKUERGS1V3SjlFQnIvUDdpLzM5NlJGOFRlSlRvYWR6?= =?utf-8?B?UE9iSEZ1Si9tYTI2QVhLbVRCamo2Nm81Q0JvOEFtVFhpZlFNd3VDZFh6RGQy?= =?utf-8?B?b1lVOWUzZldjWXdWbk40aHViWkRkb1h0VDEvZHBLbWU0MWVJaWxRRWZEbmZI?= =?utf-8?B?UHFhLzZ5TE9mc0ZJbHNFU0Z1R1Z4M2hCYUNicjc3NzIxQXFiVGxWejViMjVY?= =?utf-8?B?ejNzeUVINmE4QllCamkwbU5pOTlSeVpQeU4vZlFjVHZJRUVxVVFGNVhoNFZw?= =?utf-8?B?Y0pYVUx5dXVBVnh0L1d1RVU5SFpBSU5TeFhHeTVreWdhNG5MNGtwUFo4SWEx?= =?utf-8?B?Q1VHT3pkQ3NQVzNrT2tqcUZBTXhjSXlKejNybGpDWENVRkpWSXJZUW01MEJv?= =?utf-8?B?amNEK0lxcUNhbzY2ejFqRU9DS3lmbXlzcnZRYTFmcWZZTFZTSnBibnI3czIv?= =?utf-8?B?TlNWdzNsYnRRS1MwcVFGZVhUU0hnSTgxNXJrRjc3NE1ROHc4UVBHMEYxNGpY?= =?utf-8?B?czJEdmxqdVhFdXhMc1lmZXRwY1dIbmJnNWtzMXdWMEFXQ2lSTlREVndPTHdw?= =?utf-8?B?NnZOK05EbnhhYjRQMkxGd3ZNZDBaK3Fua25ZNm1mdXhBOWFnV0loVXQwTHV5?= =?utf-8?B?bVdJNXJMemhFNGRMQnZKQldRWlllZ1AyL3lpWXo1aTlKMy9PdzJtQkRzWllx?= =?utf-8?B?YXVPclRqWmhUS0kxcmR1RUFONkI0V1V3VEt6RjM2SnRQaHBkQVVYWEp4Sks4?= =?utf-8?B?UDNNZEYwdFR2bHNmVW9Ib00wd1ZwbExHUzc4czVpenRDUXl1NGpSSUNBRGcx?= =?utf-8?B?THd0UlBnSUFoc2hjdE1IQXp0azhNeHIzTmZ1TlFtVGJPdHV2eVVReUY1VkNM?= =?utf-8?B?czJ0MnRSZE1HMWtpY25iNGxsd2gxMkRXeFhHNHVNUUNMQ2ZzQjFlQlpKRDV3?= =?utf-8?B?U0hEbGo5QkhRMnk1aHArVERLdThldGFYOWw0cWhVb21DZEhoUlZHYlRNVjJs?= =?utf-8?B?Wk1tRkFpRnc0NzJWc0lwcDVFRXV6VHA2U3lURE9iL3pud1I3ZlQvUXhLRi9N?= =?utf-8?B?S01qUlFrNEM0VWp4ZytQdVZuUkhVU0RZYUpNdlpuN25lWU51MGRaODJhNENI?= =?utf-8?B?S0JheEtUU1pNd2pCY3dESHBtWlpjbmlvamZ0eDMyNm5KdU14N0NvRU5LcS82?= =?utf-8?B?dUJtODdVYnZodFRZZXZDa0JtTXc1cVRJUllsN1hsOWdlVlZzYzhkTGMrTDQ1?= =?utf-8?B?clBlUk1uTm51L0Z6ODVkSmpMb2FyUnpSRTJSd3NncFNoTUgydUdoNkg3M0pm?= =?utf-8?Q?+YO2WG2G1vQ=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BL1PR12MB5851.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(366016)(7416014)(10070799003)(1800799024);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?NkZ2WE1BV3NwUHFLSnoxaVdXUGhrb3BhWDJEWC8vazFJaTFRL05xU2R3S0RB?= =?utf-8?B?VTZIekpZWlJrM0lTZjM4VVBnT0M3Q3hYaEVxSm9zVDlrYkJITlZlY0RZQ0tB?= =?utf-8?B?V0g3UTdLdHFYSS9GTFRaZldkaFRId2dHMFN1dFVMVjVuTXRPbmxLZ0l1SCtN?= =?utf-8?B?UWh1aE1VVml0dDFUeTVTWGVnS0NJZDBqSE1aOWpxTkVsVVFVdUNTQkxOYzFY?= =?utf-8?B?Nk1xN2g3eXpQM0hBTWlHd1REMU5lNTQzNWRsU2l5eURTWjVKY3h1NG83TU90?= =?utf-8?B?S0M1amV6L1djM0VYQktRa3F0YXk1STNnRTlsWW02UFNYZnN6M2NFUS83RTV1?= =?utf-8?B?cGVNT1pHeWQ4VHhsK3FrZytYQ1BwTFQrL2NzOEtXWk1zeHVXZFJ4YU56VzZl?= =?utf-8?B?UFVtSFo4QVpPNWFiL2g0U0pqN2dBNXVVdzUwVTZER0NNbS9NSHp6QldKZy9j?= =?utf-8?B?T3Y2ZjFiN0ltQ0gxZDhRYzlPQ0tZaE0yeUNoSzNTY1lHOEl3VTRYd2MwR3FP?= =?utf-8?B?V3dMdk0rY21CNGx5NUdRM3NEREhvMUFqb0RNWFBEV2dTZ3Fkc1gwVE8zajlr?= =?utf-8?B?SzJZb0VxTW9YSEZua3U0cnVuZk93ZGlUYWVjdFZTRGJVbzh4V2lRMHlWZFg1?= =?utf-8?B?aGpIcU1lbFRkd3lHc21pNm5kc0U1M04zOGNLdTlkK21wSklJbi9WaEJCRnU4?= =?utf-8?B?Uy9PMitlSmNKTXR1SjBKUjNSNXllanFQeEt5MlEwdlZzOTZ4cVJmbExySTFS?= =?utf-8?B?OGErVlJ6cndYVU5OQnRKeTlWWFhvelBENzM2eUxiSlp1QXczdElpeUthRGsr?= =?utf-8?B?VExYeUhia1hML2hjaFBuckw0dWdHZWFwZkNScDBBdXI4bUNia2E2SmIrQlpt?= =?utf-8?B?YlNXYTc5eXRFZmpLbjFNdjN1OHhLT0ZjYXZoUlo1VVh5MnlmZUlRZGIxVUxF?= =?utf-8?B?WHRjQjRZR2V4ZlplK0JIK1ZjcUlzSVpubDdudFZHRmhhVFU2eGZTT2RTMC9O?= =?utf-8?B?cGpjYXpXWTcyK1pjV0dsSlJieUdFVGtFNU1VeFhHY2FEc1JmT0dMNHZYcTlJ?= =?utf-8?B?TFA5SndFNEJoOUxpL1hldkl4ZzlEQ1Jock1jYldkVEZ0SnAzYnd3QnlKUVJl?= =?utf-8?B?dGZDenhORlNUK3VqbEwvcWZSVG1LQ29TL0cvT1FCYVZSSWcrOGJ3YkZPRU0w?= =?utf-8?B?QzVHZ2RuTWNhdHFoOHJ1RnBuRzRPYlUyMVIyOCtOREpFbHpDaGJMZGdJaHNV?= =?utf-8?B?UzZ5c1pvVzFyMXRDYzhnZUdRZzF0Q0creGVidWluNmpoOTIvelBWbHRXenNL?= =?utf-8?B?K0dYTmNNMzRQZGVNQi9OZXhxK3hxT0lEMWdxbXd3RlI4WEVtUmFXNEVRTEFS?= =?utf-8?B?RzNiZXJNMlpoYWhvWjZoU2lrWTFwMitET0pvK1dXREh1T3ZyNzZISHlMTE85?= =?utf-8?B?WENIdWNnNkNOb0pnUkxoeHhuOUVCZWpxdzJJVnQ2OEg1VlpwNmFKdGdNUUNs?= =?utf-8?B?UTY4amExNS9FUFZESXdxUzZzcHloK3JNUUFJdEdja2VUYXJSTGJ6NGcxbVFH?= =?utf-8?B?VmVRT3JzTVZrWFkvR2RZcDBZL2t4NEQwQjN3emtXVVRlSDNwcXFWSjBpNEdh?= =?utf-8?B?MW9yNk1IaU15VlVvc2Q2YU9XRXg1Y3lCMFZkYVF4OXBJdHZ4RlJFYXNBMUd4?= =?utf-8?B?MDRQWmsxTHVXdkRoZFEzUm9OM2xSNlRxNXJybkdTdmw0Y1lwaXBVQ1RZdmxS?= =?utf-8?B?dXNINXFBNEVWZllxNm1FRTJUdkIyYWVaWjhETkN1MEVZaHZHbFRFRWxrNXlV?= =?utf-8?B?TVZuMGdaRTJGK3ZlSjF6a24xdllsaDVRRCtaUkZGKzRrSXBGUGt5N3lXSjU5?= =?utf-8?B?d3d2cFcrZW4vM2hrVnlRdk04VlVhNGdKVWF6MklsMkxoMVd6QkNIaHZPT2dm?= =?utf-8?B?eXUzNTdXbG1lVlFIMUZpV3haMTE0bUZGWmJ0b01KeUgzVktJcjcxSFo5dVVM?= =?utf-8?B?NEVkdTNsMDQ3OWwwVU50U1RTMlo2RVVBWm9TS2VnZUFoYjhLRWp1ditKNnpC?= =?utf-8?B?cjRic0o5Z28vY0lUSGhoZW0wWi9scnFGL3FPWTZYc1FnY2sxaHV1dDhtMFRF?= =?utf-8?B?ZHdJWVdlRDQ1VFVpMzBzU3hsRDFhc0JSQ0x2RTcvQ09GT1pXZVpVd0RPb0g0?= =?utf-8?Q?G4WUCYHYm59KPXPhiFjJ9t0mK6J29pjJ31Z9Bm3p8Qvl?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: fc4fb341-882a-4a19-dee7-08ddc8e29088 X-MS-Exchange-CrossTenant-AuthSource: BL1PR12MB5851.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Jul 2025 05:42:37.2367 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: PWqWGfEIT3Z2ADAjIkQi4Y5umyScdZx5PyT82iQ/5+YLOigC9XvyvsVsbOMMYsvdSTBM8NPx0dsNO/Lc32c0vA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR12MB9226 X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 405E91C0007 X-Stat-Signature: hxse79icyjxu7mapciotwqo6nsjxtxar X-Rspam-User: X-HE-Tag: 1753162960-641883 X-HE-Meta: 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 eYs3UR1X EICoxfezxioCZcSTio1kBobh18YbU1JyMxdOwz9IBrgLA2cbmEb5Jh6yCSvYqB7w1RUc7xVZ5DPdgbbyL2HIZ2JQyzkfv0v42KF70jOjD8JY10I/9SPxaDQOOlwSh5OXSyVq+2jO7kA2O4DR/AnuT+uOo8rIAxAOdvXQ+E+7GrE4sC9P9pBN4WDzDjVTYoSPD9pfO2vXmEJ57kECRJaQmyoLWfWe7xYNRJOO9XX/zf51FgmBBehrbaI+DXsEHK/GjN12C95TgYpoEx5TaeTKUpD7p0zqe3M7Lqif2DUjixUY6tTOIeLMU0AJlq1JE9+/5ahU5MZPgOXyq5XyhIzOwqfesT8WPQzOzDM5lI7xZAtBQDzqtI8ior1/96c25leHWE8jyFeHCy8vlkvhHSUfjoC4QkLmMmgVsaNaR/Mr5Lfkc3BDgi4MlPmY0AaHMt8U5Tlt3zMT7ryNdUPVJh4fvMPX0VFohJei0Hch8dpge/O8JXtY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 21/07/2025 9:59, Christoph Hellwig wrote: > On Fri, Jul 18, 2025 at 02:51:08PM +0300, Yonatan Maman wrote: >> From: Yonatan Maman >> >> hmm_range_fault() by default triggered a page fault on device private >> when HMM_PFN_REQ_FAULT flag was set. pages, migrating them to RAM. In some >> cases, such as with RDMA devices, the migration overhead between the >> device (e.g., GPU) and the CPU, and vice-versa, significantly degrades >> performance. Thus, enabling Peer-to-Peer (P2P) DMA access for device >> private page might be crucial for minimizing data transfer overhead. > > You don't enable DMA for device private pages. You allow discovering > a DMAable alias for device private pages. > > Also absolutely nothing GPU specific here. > Ok, understood, I will change it (v3). >> + /* >> + * Don't fault in device private pages owned by the caller, >> + * just report the PFN. >> + */ >> + if (pgmap->owner == range->dev_private_owner) { >> + *hmm_pfn = swp_offset_pfn(entry); >> + goto found; > > This is dangerous because it mixes actual DMAable alias PFNs with the > device private fake PFNs. Maybe your hardware / driver can handle > it, but just leaking this out is not a good idea. > In the current implementation, regular pci_p2p pages are returned as-is from hmm_range_fault() - for virtual address backed by pci_p2p page, it will return the corresponding PFN. That said, we can mark these via the hmm_pfn output flags so the caller can handle them appropriately. >> + hmm_handle_device_private(range, pfn_req_flags, entry, hmm_pfn)) > > Overly long line here. > will be fixed (v3)